Tray washing system

ABSTRACT

A tray washing system includes conveyors which transport compartmented food service trays from a tray receiving mechanism to inverting and scrapping mechanisms and through washing, rinsing and drying mechanisms to a stacking mechanism. The receiving mechanism restricts trays to insertion in a predetermined orientation in which the food receiving surfaces face upwardly, and the inverting mechanism inverts each tray so that the food receiving surface faces downwardly. As each tray is inverted, the scrapping mechanism discharges substantially the entire contents of a cleaning fluid reservoir onto the food receiving surface of the tray, and thereby dislodges refuse and silverware that may be on the tray. The washing, rinsing and drying mechanism apply a water-detergent solution, rinse water, and drying air to the trays, respectively, and the stacking mechanism deposits the trays onto a mobile self-depressing tray receiver. The tray washing system further includes a silverware separating and soaking mechanism comprising a chute which receives cleaning fluid and refuse and silverware entrained therein, a dam which removes the heavier silverware from the cleaning fluid, and a door in the bottom of the chute for dropping the silverware into a soaking sink.

United States Patent 1 Kitterman et a].

[ Nov. 20, 1973 TRAY WASHING SYSTEM [76] Inventors: Lawrence PeteKitterman, 1309 Woodway, Hurst; Howard Gene Rice, 1109 Hadrian Ct.,Irving, both of Tex.

[22] Filed: Jan. 20, 1972 [211 App]. No.: 219,583

Related US. Application Data [62] Division of Ser. No. 89,401, Nov. 13,1970.

Primary Examiner-Robert L. Bleutge Att0rneyMichael A. ONeil 57 1ABSTRACT A tray washing system includes conveyors which transportcompartmented food service trays from a tray receiving mechanism toinverting and scrapping mechanisms and through washing, rinsing anddrying mechanisms to a stacking mechanism. The receiving mechanismrestricts trays to insertion in a predetermined orientation in which thefood receiving surfaces face upwardly, and the inverting mechanisminverts each tray so that the food receiving surface faces downwardly.As each tray is inverted, the scrapping mechanism dischargessubstantially the entire contents of acleaning fluid reservoir onto thefood receiving surface of the tray, and thereby dislodges refuse andsilverware that may be on the tray. The washing, rinsing and dryingmechanism apply a water-detergent solution, rinse water, and drying airto the trays, respectively, and the stacking mechanism deposits thetrays onto a mobile self-depressing tray receiver. The tray washingsystem further includes a silverware separating and soaking mechanismcomprising a chute which receives cleaning fluid and refuse andsilverware entrained therein, a dam which removes the heavier silverwarefrom the cleaning fluid, and a door in the bottom of the chute fordropping the silverware into a soaking sink.

28 Claims, 13 Drawing Figures Patented Nov. 20, 1973 3,773,058

7 Sheets-Sheet 1 FIG;

FIG. 2

Patented Nov. 20, 1973 7 Sheets-Sheet 2 Patented Nov. 20, 1973 3,773,058

7 Sheets-Sheet 15 WW FIG. 4

Patented Nov. 20, 1973 7 Sheets-Sheet 4 205 202 FIG. 8

L -/36 l e Patented Nov. 20, 1973 7 Sheets-Sheet 5 Patented Nov. 20,1973 7 Sheets-Sheet 6 n w-SEW Patented Nov. 20, 1973 7 Sheets-Sheet 7BACKGROUND OF THE INVENTION This invention relates to a tray washingsystem, and more particularly to a fully automated system for cleaningcompartmented food service trays.

Various institutions, particularly elementary schools, now serve lunchesand other meals on compartmented food service trays, rather than onconventional tableware, such as dinner plates, salad plates, saucedishes etc. This is advantageous in that when compartmented food servicetrays are employed, the purchasing, stocking, distributing, collectingand washing of ware is reduced to a single item. Also, small childrenare considerably more adept at-handling a compartmented food servicetray than they are at handling the numerous tableware items that must beused when a meal is served in the conventional manner.

The main disadvantage that has been experienced in the use ofcompartmented food service trays relates to the human effort involved inwashing the trays after each meal. At the present time, tray washingincludes manually scraping each tray, manually loading each tray into adishwashing machine and to subsequently manually unloading each trayfrom the machine. Because conventional dishwasing machines are notdesigned for use with compartmented food service trays, it is oftennecessary to manually inspect each tray after washing, and to re-washmany of the trays. At todays labor rates, any system involving so muchmanual labor can be prohibitively expensive. Also, due to socialconnotations, it is often impossible to hire dishwashers, even thoughgood salaries are offered.

One approach to solving the foregoing'problern involves the use ofdisposable compartmented food service trays. In order to reduce volumeof material involved, machines for shreading and/or compactingdisposable trays and the food and paper refuse associated therewith havebeen proposed. Unfortunately, the use of presently available disposablecompartmented food service trays is not wholly satisfactory. Forexample, it costs more to purchase disposable compartmented food servicetrays than to wash conventional, permanent-type compartmented foodservice trays, so that no real savings are realized. Also, when ashreading and/or compacting machine is employed, the use ofcompartmented food service trays necessitates the handling of a greatvolume of refuse. Perhaps most importantly, presently availabledisposable compartmented food service trays are flimsy in constructionand unappetizing in appearance, and are therefore unsatisfactory tostudents, dieticians and educators.

The present invention comprises a fully automated compartmented foodservice tray cleaning system. In accordance with the preferredembodiment of the invention, trays are moved in timed sequence to amechanism that pours a cleaning fluid over each tray and thereby removesrefuse and silverware from the tray. Thereafter, the trays are movedthrough washing, rinsing and drying stations to a mechanism thatautomati cally deposits the trays on a mobile self-depressing trayreceiver. Preferably, each tray is loaded into the system by the personwho has used the tray so that all of the manual labor that hasheretofore been necessary in the washing of compartmented food servicetrays is completely eliminated.

DESCRIPTION OF THE DRAWINGS A more complete understanding of theinvention may be had by referring to the following Detailed Descriptionwhen taken in conjunction with the drawings, wherein:

FIG. 1 is a top view of a compartmented food service tray;

FIG. 2 is a perspective view of a tray washing system employing thepresent invention;

FIG. 3 is an enlarged perspective view of the tray receiving, trayinverting, scrapping, and silverware separating and soaking mechanismsof the tray washing system shown in FIG. 1;

FIG. 4 is a schematic illustration showing various steps in theoperation of the tray inverting mechanism;

FIG. 5 is a sectional view taken generally along the line 5-5 in FIG. 3in the direction of the arrows;

FIG. 6 is an exploded view of the drive mechanism of the tray receiving,tray inverting, scrapping mechanism and silverware separating andsoaking mechanisms;

FIG. 7'is a longitudinal sectional view of the tray washing systemshowing the tray washing, rinsing and drying mechanisms thereof;

FIG. 8 is a perspective view illustrating the operation of certainportions of the tray washing, rinsing and drying mechanisms shown inFIG. 7;

FIG. 9 is a perspective view showing the tray stacking mechanism of thetray washing system;

FIG. 10 is an enlarged side view of a portion of the mechanism shown inFIG. 9;

FIG. 11 is a perspective view of a portion of the mechanism shown inFIG. 10, and

FIGS. 12 and 13 are top and side views, respectively, of the operatingportions of the tray washing system.

DETAILED DESCRIPTION Referring now to the drawings, and particularly toFIG. 1 thereof, a compartmented food service tray T is shown. The tray Tis preferably formed from a durable material that is capable ofwithstanding repeated washings, such as plastic, fiberglass, or metal.The upper surface U of the tray T comprises a food receiving surfacethat is divided into a number of food receiving compartments F and asilverware receiving compartment S. It will be understood that the trayT actually comprises a sheet of uniform thickness, and that thecompartment F and S comprise depressions formed in the sheet, so that agroove extends between the silverware compartment S and the remainder ofthe tray T.

Compartmented food service trays of the type shown in FIG. 1 are used inelementary schools to serve school lunches. Typically, a quantity oftrays sufficient in number to serve all of the students is delivered toone or more serving stations. At the serving stations, various fooditems are deposited directly on the food receiving surface of each tray,and the tray is then delivered to a student. The student also receivesvarious pieces of silverware and additional food items, such as abeverage and a dessert. It will be understood that the latter items arenormally distributed in individual cartons or containers.

After receiving his tray, each student carries the tray to a table,where the lunch is eaten. Upon completion of the meal, the studentscarry the trays to a refuse disposal area where paper refuse, i.e., milkcartons, straws, napkins, etc, from the meal is deposited in trashcontainers. Then, the students deposit the trays for cleaning with allrefuse from the meal still on the tray and simultaneously depositsilverware in a chute that leads to a silverware soaking sink. It willbe understood that since the lunch was served directly on the uppersurface of the trays in the food receiving compartments thereof, thetrays must be scrapped, thoroughly washed and sterilized before they canbe returned to the start of the cafeteria line for use in the next meal.

Referring now to FIGv 2, a tray washing system employing the presentinvention is shown. The system 20 is adapted to atuomatically cleancompartmented food service trays of the type shown in FIG. 1, andcomprises: a tray receiving mechanism 22; a tray inverting mechanism 24;a scrapping mechanism 26; washing, rinsing and drying mechanisms 28, 30and 32; and a tray stacking mechanism 34. The tray washing system 20further includes a silverware separating and soaking mechanism 36.

The structural details of the tray receiving, tray inverting, scrapping,and silverware separating and soaking mechanisms of the tray washingsystem 20 are best shown in FIG. 3, wherein the functional components ofthe tray washing system are shown in full lines and the housing andother non-functional components are shown in phantom lines. The trayreceiving mechanism 22 includes a plate which may comprise a portion ofa wall separating a school lunch room from a school kitchen. The plate40 has a passageway 42 formed in it through which compartmented foodservice trays are inserted into the tray washing system 20 by the usersof the trays. The edges of the plate 40 define the passageway 42 andinclude spaced pairs of opposed surfaces 44 which prevent the insertionof two stacked trays through the passageway 42. An upstanding ridge 46formed in the bottom of the passageway 42 receives the groove betweenthe silverware compartment and the food compartments of each tray, andthereby prevents the insertion of the trays other than with thesilverware compartment positioned to the right and the food receivingsurface facing upwardly.

A tray blocking member 48 is pivotally supported on the tray washingsystem 20 just beyond the passageway 42 in the plate 40. The trayblocking member 48 is normally positioned in the path of trays insertedthrough the passageway 42, and therefore prevents the insertion of traysin an endwise orientation. Two pairs of rollers 50 are pivotallysupported at the opposite sides of the tray washing system 20 and areinterconnected by a bar 52 that extends under the tray blocking member48. The rollers 50 cooperate with the surface 44 of the plate 40 toprevent the insertion of two stacked trays. Also, a properly insertedcompartmented food service tray engages the rollers 50 and pivots therollers upwardly. This action pivots the bar 52 upwardly, which in turnpivots the blocking member 48 upwardly, out of the path of the tray. Thepair of rollers 50 are arranged to amintain the blocking member 48 outof the path of a properly inserted tray until the tray clears the blocking member 48.

From the foregoing, it will be understood that the passageway 42, theridge 46, and the tray blocking member 48 cooperate to constrain traysinserted into the tray washing system to a predetermined orientation.Properly oriented trays inserted through the passageway 42 are engagedwith a conveyor 54 comprising a pair of V-belts 56 by the rollers 50.The V-belts advance each tray into engagement with a triangulariyshapedtray spacer member 58 comprising a portion of a tray timing mechanism60. The spacer member 58 is normally positioned in the path of traysentering the tray washing system 20, and therefore normally prevents themovement of the trays into the tray washing system 20 under the actionof the conveyor 54. At a predetermined point in each operating cycle ofthe tray washing system 20, a drive mechanism 62 actuates the timingmechanism 60 to pivot the spacer 58 out of the path of the trays,whereupon the conveyor 54 advances one tray into the tray washing system20. By this means, the timing mechanism 60 assures a predeterminedspacing between compartmented food service trays passing through thetray washing system 20. Because of its triangular shape, the spacer 58enters the space between trays inserted sequentially through thepassageway 42, and thereby prevents the insertion of tray other than atthe proper point in the cycle of operation of the tray washing system.

Upon release by the timing mechanism 60, each tray is transported by theconveyor 54 to the end of the V- belts 56, whereupon it is engaged by apin-type conveyor 64. The conveyor 64 includes a plurality of pins 66spaced to receive trays from the conveyors 54 and to transport each trayentering the tray washing system 20 from the receiving mechanism 22through the tray inverting mechanism 24. During this movement, the trayinverting mechanism 24 inverts each tray from its initial orientationwherein its food receiving surface faces upwardly to an orientationwherein the food receiving surface of the tray faces downwardly.

The tray inverting mechanism 24 includes a first pair of arms 68 whichare supported for pivotal movement about the axis of a shaft 70 underthe action of gravity. As the tray moves through the tray washing system20 under the action of the pin-type conveyor 64, a pair of hooks 71formed on the ends of the arms 68 engage the forward edge of the tray,whereupon the arms 68 cooperate with the conveyor 64 to pivot the trayinto a vertical orientation. As the tray approaches the verticalorientation, the drive mechanism 62 operates through a rod 72, a lever73, a rod 74 and a lever 75 to pivot a second pair of arms 76 about theaxis of a shaft 78. This action engages a pair of hooks 79 formed on theends of the arms 76 with the same edge of the tray that is engaged bythe arms 68, whereupon the arms 76 pivot the tray from the verticalorientation to a horizontal orientation in which the food receivingsurface of the tray faces downwardly.

The tray inverting mechanism 24 further includes an arm 80 mounted forpivotal movement with the arms 76. A tray engaging member 82 is securedto one end of the arm 80 and a roller 84 is secured to the other end. Asthe arm 80 pivots downwardly with the arms 76, the roller 84 follows theupper surface of the cam 86 and cooperates with the cam 86 to urge thetray engaging member 82 outwardly. This action grips the tray betweenthe tray engaging member 82 and the hooks 79 of the arms 76.

The functions of the various components of the tray inversion mechanism24 of the tray washing system 20 will be better understood by referringto FIG. 4, wherein various steps in the operation of the tray invertingmechanism 24 are schematically illustrated. As a compartmented foodservice tray is moved through the tray washing system 20 by the pin-typeconveyor 64, it is engaged by the hooks 71 of the first pair of arms 68.Further forward motion of the tray under the action of the conveyor 64causes the forward end of the tray to pivot upwardly about the axis ofthe shaft 70.

As the tray reaches a substantially vertical orientation, the drivemechanism 62 pivots the hooks 79 of the arms 76 into engagement with thesame edge of the tray that is engaged by the arms 68. Upon further movement of the tray by the conveyor 64, the tray moves over center,whereupon the arms 68 drop outof engagement with the tray under theaction of gravity. Them, the arms 76 complete the inversion of the tray.It should be noted that during the latter portion of the tray inversionprocess, the arms 76 push the tray forwardly to a point beyond theforward end of the conveyor 64. 8

Referring again to FIG. 3, the scrapping mechanism 26 of the traywashing system 20 includes a cleaning fluid reservoir 90 that ispivotally supported by a pair of trunnions 92 and a pair of yokes 94. Apipe 96 extends into the reservoir 90 through an elongated slot 98formed in the upper surface thereof, and a cleaning fluid iscontinuously supplied to the reservoir 90 through the pipe 96. Apivotally supported shaft 100 extends under the reservoir 90 and an arm102 extends perpendicularly from the shaft 100. Nonnally, the reservoir90 is maintained in a retracted position wherein the reservoir 90 restson the arm 102, and the arm 102 rests on a stationary shaft 104.

The shaft 100 is connected to the drive mechanism 62 through a bellcrank 106 and a rod 108. As each tray passing through the tray washingsystem 20 is manipulated into a substantially vertical orientation bythe tray inversion mechanism 24, the drive mechanism 62 moves the rod108 upwardly. The action pivots the arm 102 upwardly about the axis ofthe shaft 100, and therefore tilts the reservoir 90 about the trunnions92 from the position shown in FIG. 2 to the position shown in FIG. 3.During the tilting of the reservoir 90, cleaning fluid pours out of thereservoir onto the food receiving surface of the tray. This actionscraps the tray, that is, the cleaning fluid flowing out of thereservoir 90 dislodges refuse and any silverware that may be on thetray. It has been found that the scrapping action of the presentinvention is superior to that of prior tableware cleaning systems inthat by dumping substantially the entire contents of the reservoir 90onto the food receiving surface of each tray passing through the traywashing system 20, the removal of all refuse and silverware from eachtray is virtually assured, due to the weight and even distribution ofthe cleaning fluid flowing across the food receiving surface of thetray.

Cleaning fluid flowing over the food receiving surface of a tray fromthe reservoir 90 entrains refuse and any silverware that may be on thefood receiving surface, and carries the refuse and silverware into ahopper 120. From the hopper 120, the cleaning fluid and the refuse andsilverware entrained therein flow into the chute 122, and through thechute 122 into a refuse receiving mechanism 124. The refuse receivingmechanism 124 is conventional in design and operates to separate refusedislodged bythe scrapping mechanism 26 from the cleaning fluid employedin the scrapping mechanism. In accordance with the preferred embodimentof the invention, the cleaning fluid from the refuse receiving mechanism124 is reused in the scrapping mechanism 26, that is, cleaning fluidfrom the refuse receiving mechanism 124 is returned to the reservoirthrough the pipe 96.

As is best shown in FIG. 2, the silverware separating and soakingmechanism 36 of the tray washing system 20 includes a silverware chutethat slopes downwardly from a silverware receiving passageway 132 formedin the plate 40 to a silverware soaking sink 134 which includes aremovable silverware collecting basket (not shown). Preferably, allsilverware is removed from each tray and is inserted into the silverwareseparating mechanism 36 through the passageway 132 before the tray isinserted through the passageway 42. It will be appreciated, however,that elementary students will often neglect to remove silverware fromtheir trays before inserting the trays into the passageway 42. To thisend, the chute 122 is provided with a dam 136 which disentrainssilverware from the cleaning fluid employed in the scrapping mechanism26 as the cleaning fluid flows through the chute 122. As is best shownin FIG. 5, the dam 136 is positioned in the bottom of the chute 122 atthe end thereof adjacent the refuse receiving mechanism 124. During theflow of cleaning fluid and refuse and silverware entrained hereinthrough the chute 122, the dam 136 engages the heavier silverware andrestrains the silverware from further movement through the chute 122,while at the same time permitting the cleaning fluid and refuse to flowout of the chute 122 and into the refuse receiving mechanism 124. Itwill be understood that by providing a chute of proper length andinclination, it is possible to disentrain silverware from cleaning fluidwithout providing a dam, per se.

As is best shown in FIG. 3, the silverware separating and soakingmechanism 36 further includes a normally closed trapdoor 138 that isconnected to the drive mechanism 62 through a link 140. At a point in acycle of the tray washing system 20 when little or no cleaning fluid isflowing through the chute 122, the drive mechanism 62 opens the trapdoor138. As is best shown in FIG. 5, the trapdoor 138 is positioned directlyabove the silverware chute 130. Thus, any silverware that enters thetray washing system 20 on a compartmented food service tray is entrainedin cleaning fluid by the scrapping mechanism 26, and is thereafterdisentrained from the cleaning fluid by the dam 136, and is finallydeposited in the chute 130 by the trapdoor 138. Once the silverwareenters the chute 130, it enters the silver ware soaking sink 134 in thesame manner as if it had been inserted into the chute 130 through thesilverware passageway 132.

Referring now to FIG. 6, the construction of the drive mechanism 62 ofthe tray washing system 20 is shown in detail. The drive mechanism 62includes a sprocket that is continuously rotated by the motor (notshown). The sprocket 150 drives a sprocket 152 and a large sprocket 154through a chain 156. A cam 15 is mounted on the sprocket 154 forrotation thereby. Once during each revolution of the sprocket 154, thecam 158 engages a bell crank 160 which is connected to tray spacermember 58 by a link 162. The cam 158, the bell crank 160, the link 162and the spacer 58 are so arranged that upon engagement of the cam 158with the bell crank 160, the spacer 58 is pivoted out of the path oftrays inserted into the tray washing mechanism through the passageway42.

Somewhat later during each revolution of the sprocket 154, the cam 158engages a roller 164 that is mounted on a pivotally supported lever 166.The lever 166 is connected through the link 140 to the trapdoor 138 ofthe silverware separating and soaking mechanism 36 so that, uponrotation of the gear 150, the cam 158 actuates the trapdoor 138 of thesilverware sepa rating mechanism 36. Thus, upon rotation of the sprocket154, the cam 158 actuates both the spacer 58 and the trapdoor 138 at theproper point in each operating cycle of the tray washing system 20.

The drive mechanism 62 further includes a pair of cams 168 and 170,which are connected to the rod 72 of the tray inverting mechanism 24 andthe rod 108 of the scrapping mechanism 26, respectively. The cams 168and 170 are pivotally supported on a pair of bolts 172 and 174,respectively, and have camming slots 178 and 180 formed through them.The slots 178 and 180 receive a drive pin 182 mounted on the sprocket154 and, accordingly, upon rotation of the sprocket 154, the drive pin182 oscillates the cams 168 and 170 to provide the motions necessary forthe operation of the tray inverting mechanism 24 and the scrappingmechanism 26.

Referring now to FIG. 7, the conveyor 64 of the tray washing system 20drives a pintype conveyor 190 through a chain and sprocket drivemechanism 191. Each tray passing through the tray washing system 20 istransported by the conveyor 64 and arms 76 into engagement with theconveyor 190, and is thereafter engaged by a pin 192 projecting from theconveyor 190 for transportation along a path 194 defined by a pluralityof pairs of opposed rollers 196. The path 194 extends through thewashing mechanism 28, the rinsing mechanism 30, and the drying mechanism32 of the tray washing system 20, and accordingly, each tray passingthrough the tray washing system is sequentially washed, rinsed and driedas it is transported by the conveyor 190.

The washing mechanism 28 of the tray washing sys tem 20 is separatedfrom the scrapping mechanism 26 by a baffle 199 and includes a pair ofpipes 200 positioned on opposite sides of the path 194 defined by theopposed rollers 196. In use, a washing fluid, which may comprise asolution of hot water and a suitable detergent or any other suitablewashing fluid is directed into the pipes 200 and is discharged from thepipes through a plurality of spray heads 202 mounted thereon. As is bestshown in FIG. 8, the pipes 200 are connected to a lever 204 by a pair oflinks 206 and a pair of levers 208. The lever 204 is mounted forrotation by the conveyor 64, and the links 206 and the levers 208 arearranged to oscillate the spray heads 202 upon rotation of the lever204. By this means, contact between washing fluid discharged from thespray heads 202 and all portions of each tray passing through the traywashing mechanism 20 is assured.

Referring again to FIG. 7, the rinsing mechanism of the tray washingsystem 20 is separated from the washing mechanism by a baffle 209 andcomprises a pair of pipes 210 positioned on opposite sides of the path194 defined by the opposed rollers 196. in use, a rinsing fluid, whichpreferably comprises extremely hot water, is directed into the pipes 210and is discharged from the pipes through spray heads 212 mountedthereon. Rinsing fluid from the pipes 210 engages the trays passingthrough the tray washing system 20 under the action of the conveyor 190,and thereby clears the trays of washing fluid that was applied to thetrays by the washing mechanism 28.

The drying mechanism 32 comprises a pair of triangularly shaped ducts214 positioned on opposite sides of the path 194 defined by the rollers196. The ducts 214 direct a drying fluid across the trays passingthrough the tray washing system 20, and thereby strip the trays of therinsing fluid that was applied to the trays by the rinsing mechanism 30.The drying fluid preferably comprises high velocity air, which may beheated, depending upon the temperature of the rinsing fluid, and thenature of the trays.

From the foregoing, it will be understood that after all of thecompartmented food service trays used in a particular meal have beenwashed by the tray washing system 20, all of the silverware that wasused in the meal is located in the silverware soaking sink 134. inaccordance with the preferred embodiment of the invention, thesilverware is removed from the sink 134 and is placed in a speciallydesigned silverware washing rack (not shown). The rack is thenpositioned in the tray washing system 20 through a door 216, and isthereafter transported through the washing mechanism 28, and the rinsingmechanism 30. During this action the mechanisms 28 and 30 apply thewashing fluid and the rinsing fluid to the silverware, respectively, sothat the silverware is thoroughly cleaned and sanitized.

in use, the specially designed silverware rack is positioned on two ofthe upper rollers of the pairs of opposed rollers 192 and is transportedthrough the mechanism 28 and 30 by the conveyor 190. After passingthrough the mechanism 30, the rack moves up a ramp 217 and intoengagement with a switch 218, which upon actuation interrupts theoperation of the conveyor 190. Then, the silverware rack is removed fromthe tray washing system 20 through a door 219, and the silverware isremoved from the rack and is positioned as necessary for use in the nextmeal. Thus, the tray washing system 20 functions not only to washcompartmented food service trays, but also the silverware that is usedin conjunction with the trays in serving a meal.

ln the operation of the portion of the tray washing system 20 shown inFIG. 7, washing and rinsing fluids are sprayed onto each tray and aresubsequently stripped therefrom. In accordance with the preferredembodiment, the spent washing and rinsing fluids are not discarded.Instead, the runoff from the rinsing mechanism 30 and the runoff fromthe washing mechanism 28 are combined with a portion of the output ofthe refuse receiving mechanism 124 to form the cleaning fluid that isemployed in the scrapping mechanism 26. in this manner, the cost ofoperating the tray washing system is greatly reduced in that both watercosts and water heating costs are held to an absolute minimum.

Referring now to FIGS. 9, 10 and 11, the conveyor drives a pin typeconveyor 220 through a chain and sprocket drive mechanism 222 and a pairof gears 224. Each tray passing through the tray washing system 20 istransported by the conveyor 190 into engagement with the conveyor 220,whereupon the tray is engaged by a pin 226 projecting from the conveyor220 and is transported into the tray stacking mechanism 34 of the traywashing system 20. The stacking mechanism 34 in turn stacks the trays ona conventional mobile selfdepressing tray receiver 228. Theself-depressing tray receiver illustrated in FIG. 9 is conventional indesign in that it receives two parallel stacks of trays each comprisingtrays stacked upside down and one on top of another. This isadvantageous in that the trays are not contaminated by dirt, etc., whilethey are in the tray receiver.

The self-depressing tray receiver 228 is secured to the tray washingsystem by a latch mechanism 230. The latch mechanism 230 comprises apair of spring loaded latches 231 which are arranged to prevent eitherthe engagement or the disengagement of a tray receiver with the latchmechanism 230 by a straight line movement. Instead, the latch mechanism230 requires a pivoting motion in first one direction and then the otherrelative to a line extending along the conveyors 190 and 220 in order tolatch or unlatch a tray receiver. In this manner, the latch mechanism230 retains the tray receiver in the position shown in FIG. 9 unless itis intentionally removed.

The tray stacking mechanism 34 comprises a pair of inner opposed traystacking ledges 232 and a pair of outer opposed tray stacking ledges234. In use, both pairs of tray stacking ledges are initially pivotedbetween the tray receiving position illustrated in FIG. 9 and a traydepositing position in timed relationship to the movement of trays intothe tray stacking mechanism 34. Since the ledges 232 are positionedcloser to the conveyor 190, the stacking mechanism 34 initially forms aninner stack of trays in the self-depressing tray receiver 228.

When the inner stack has been completed, the stacking mechanism 34automatically discontinues the reciprocation of the tray stacking ledges232 and retains the tray stacking ledges 232 in the horizontal positionillustrated in FIG. 9. Thereafter, the conveyor 220 advances each traypassing through the tray washing system 20 across the inner traystacking ledges 232 and onto the ledges 234. The ledges 234 are pivotedfrom the tray receiving position to the tray depositing positionthroughout the operation of the stacking mechanism 34, so that after ithas formed an innerstack of trays, the stacking mechanism 34 forms anouter stack of trays in the tray receiver 228. When the outer stack hasbeen completed, a limit switch (not shown) is actuated, whereupon theoperation of the tray washing system 20 is discontinued.

More specifically, the conveyor 190 drives the tray stacking mechanism34 through a pair of cams 240 and 242. The cams 240 and 242 are mountedfor rotation by the conveyor 190 about the same axis of rotation as thelarger sprocket of the mechanism 222 and hence into engagement with apair of levers 244 and 246, respectively, each of which is supported forpivotal movement about a pin 248. Thus, during each operating cycle ofthe tray washing system 20, the cams 240 and 242 engage the levers 244and 246, respectively and pivot the levers about the pin 248.

The lever 246 is connected to a link 250. As is best shown in FIG. 11,the link 250 is in turn connected to a pin 252 that is mounted on alever 254 for rotation about an axis 256. Thus, each time the lever 244is rocked by the cam 240, the pin 252 is moved arcuately about the axis256. A lever 258 is supported on the pin 252 for actuation by the cam240 and the lever 244 through the link 250. However, the effect of theactuation of the lever 258 is controlled by a tray responsive controlmechanism 260.

As is best shown in FIG. 10, the tray responsive control mechanism 260includes a tray sensing pin 262 which is positioned in the path of theinner stack of trays in the tray receiver 228. A lever 264 is connectedto the pin 262 for pivotal movement therewith about a shaft 266. Thelever 264 is connected to a lever 268 through a link 270, and the lever268 is connected to a lever 272 for pivotal movement about a pivot 274.

The lever 272 is supported on the pivot 274 for movement between extremepositions which are defined by a pair of pins 276 and 278. A spring 280extends between the lever 272 and a lever 282 which is supported on apivot 284 for movement between extreme positions defined by a pair ofpins 286 and 288. Thus, the levers 272 and 282 and the spring 280comprise an overcentering toggle mechanism which is constrained tooccupy either the position shown in full lines in FIG. 10 or theposition shown in dashed lines therein.

As is shown in FIGS. 10 and 11, the lever 272 is connected to a link290, and the link 290 is connected to a pin 292 that is secured to theupper end of the lever 258. As is shown in FIG. 9 and 11, a link'294extends from the pin 292 to a lever 296. The lever 296 in turn controlsthe rotational position of one of the inner tray stacking ledges 232. Amechanism identical in construction and operation to that comprising theparts 252 through 296 is employed on the remote side of the traystacking mechanism 34 to control the rotational position of the otherinner stacking ledges 232. Since the cam 240 is operated by the conveyor190, it will be understood that whenever the tray sensing pin 262 ispositioned as shown in full lines in FIG. 10, the mechanism shown inFIGS. 10 and 11 and the corresponding mechanism located on the remoteside of the tray stacking mechanism 34 cooperate to deposit each traypassing through the tray washing system 20 onto the inner stack of traysin the mobile self-depressing tray receiver 228.

When a predetermined number of trays have been deposited on the innerstack of the receiver 228 the stack is depressed to such an extent thatit engages the tray sensing pin 262 of the mechanism 260. The pin 262 isthereupon rotated about the pivot 266, which in turn rocks the lever 268about the pivot 284. Sufficient pivoting of the lever 268 snaps themechanism 260 over-center, whereupon the spring 280 drives the levers272 and 282 into the position shown in dashed lines in FIG. 10. Sincethe link 290 is connected to the pin 292 which is in turn connected tothe upper end of the lever 258, movement of the mechanism 260 into theposition shown in dashed lines in FIG. 10 positions the lever 258 asshown in dashed lines in FIG. 11.

Assuming now that the cam 240 engages the level 246 while the componentparts of the mechanism 260 are positioned as shown in dashed lines, thepin 252 is again moved arcuately about the axis 256 by the link 250.However, the mechanism 260 now retains the pin 292 in alignment with theaxis 256. Thus, both the lever 254 and the lever 258 pivot arcuatelyabout the axis 256, with no resulting upward motion being imposed on thelink 294. The lever 296 is therefore retained in the position shown inFIG. 9, as is the tray stacking ledge 232 that is connected to the lever296. It will be understood that the corresponding mechanism located onthe remote side of the tray stacking mechanism 34 operates similarly toretain the other tray stacking ledge 232 in the tray receiving position.

The lever 246 is connected to a link 300 which is in turn connected to alever 302. The lever 302 is supported for pivotal movement about theaxis of a shaft 304, and is connected to a lever 306 by a link 308. Thelever 306 controls the rotational position of one of the outer traystacking ledges 234, and a similar mechanism located on the remote sideof the tray stacking mechanism 34 controls the rotational position ofthe other ledge 234. Thus, each time the lever 246 is pivoted by the cam242, the ledges 234 are pivoted downwardly. This action occursregardless of whether the inner stack on the tray receiver 228 is full,but it is effective only after the pin 262 has been actuated to positionthe mechanism 260 as shown in dashed lines in FIG. 10. Thereafter, theconveyor 220 transports trays across the inner stack of trays on thetray receiver 228 and onto the outer pair of opposed tray ledges 234.Then, the ledges 234 are rotated to form an outer stack of trays in thetray receiver 228.

When the outer stack in the mobile self-depressing tray receiver isfull, a limit switch (not shown) is actuated, whereupon the operation ofthe tray washing system 20 is stopped. Then, the tray receiver 228 isremoved from the position shown and is replaced by another, similardevice. The tray sensing pin 262 of the tray responsive controlmechanism is so positioned that it is returned to the position shown infull lines in FIG. whenever a tray receiver is removed from the traywashing system 20. In this manner, the system is returned to itsoriginal condition.

OPERATION The operation of the tray washing system in cleaningcompartmented food service trays is best illustrated in FIGS. 12 and 13.At the conclusion of his meal, each student inserts his tray through thepassageway 42 of the plate 40 with the food receiving surface of thetray facing upwardly and with the silverware receiving compartmentpositioned to the right. The tray engages the rollers 50, whereupon theblocking member 48 is pivoted out of the path ofthe tray. Upon insertionthrough the passageway 42, the tray is engaged by the conveyor 54, andis advanced by the conveyor into engagement with the tray spacer member58. At the proper point in the next cycle of the tray washing mechanism20, the spacer 58 releases the tray for movement by the conveyor 54 intoengagement with the conveyor 64.

The conveyor 64 advances the tray to the tray inverting mechanism 24which initially pivots the tray into a vertical orientation. At thispoint, the scrapping mechanism 26 dumps substantially the entirecontents of the reservoir 90 onto the food receiving surface of eachtray, and thereby dislodges refuse and any silverware that may be on thetray. After the scrapping action, the tray inverting mechanism 24continues the inversion of the tray, so that the tray passes through theremainder of the tray washing system 20 in an inverted orientation.

The tray inverting mechanism 24 delivers the tray to the conveyor 190which transports the tray through the washing mechanism 28, the rinsingmechanism 30, and the drying mechanism 32 of the tray washing system 20.During its movement, the tray is constrained by the opposed rollers 196which prevent fluttering of the tray due to the spraying actions of thewashing, rinsing and the drying mechanisms.

Upon leaving the drying mechanism 32, the tray is transported by theconveyor and the conveyor 220 to the tray stacking mechanism 34. Thestacking mechanism 34 forms inner and outer stacks of the trays on aconventional mobile, self-depressing tray receiver 228. When thereceiver 228 is full, it is disengaged from the tray washing system 20,and is thereafter employed to dispense trays during a subsequent meal.

Preferably, each student deposits his silverware in the silverware chute130. Any silverware remaining on a compartmented food service tray isdislodged during the scrapping of the tray, and comes to rest inengagement with the cam 136. In either event, all of the silverware thatis used in a particular meal ultimately comes to rest in the silverwaresoaking sink 134.

After all of the trays from a meal have been washed, the silverware fromthe meal is removed from the sink 134 by lifting the silverware baskettherefrom and is placed in a silverware rack. The silverware rack isthen inserted through the door 216 for transportation through thewashing and rinsing of the tray washing system 20. After the silverwarerack has passed through the rinsing mechanism, it is removed through thedoor 219, and the silverware is removed from the rack for use in thenext meal.

Those skilled in the art will immediately appreciate the fact thatcompartmented food service trays are useful in serving meals atinstitutions other than elementary schools, for example, summer camps,military bases, prisons, etc. Obviously, the present invention isadapted for use at any of these institutions, and is not limited to useat elementary schools. Also, the present invention is not limited to usewith the particular compartmented food service tray shown in FIG. 1.Quite to the contrary, the invention is easily modified for use with anyof the compartmented food service trays that are presently on themarket. Finally, various features of the present invention are readilyadaptable to the cleaning of tableware items other than compartmentedfood service trays.

From the foregoing, it will be understood that the present inventioncomprises a fully automated system for cleaning compartmented foodservice trays. In accordance with the preferred embodiment of theinvention, each tray is inverted from an initial orientation in whichthe food receiving surface of the tray faces upwardly, through avertical orientation, to a horizontal orientation in which the foodreceiving surface faces downwardly. While the tray is orientedvertically, a cleaning fluid is poured over the tray to dislodge refuseand silverware from the tray. After it is inverted, the tray is washed,rinsed and dried. Finally, the tray is stacked on a mobileself-depressing tray receiver. The use of the invention is advantageousin that it completeiy eliminates the manual labor that has heretoforebeen necessary to the cleaning of compartmented food service trays.

Although the preferred embodiment of the invention has been illustratedin the drawings and described in the foregoing specification, it willbeunderstood that the invention is not limited to the embodimentdisclosed, but is capable of rearrangement, modification andsubstitution of parts and elements without departing from the spirit ofthe invention.

13 What is claimed is:

l. A tray washing apparatus comprising: means defining a tray washingpath; tray receiving means positioned at the start of the path forconstraining trays entering the path to a predetermined orientation;

means for transporting food service trays along the path with the foodreceiving surfaces of the trays initially facing upwardly;

means for inverting each tray and for dumping a predetermined quantityof cleaning fluid onto the food receiving surface of each tray duringthe inversion thereof, and

means for sequentially applying washing, rinsing and drying fluids toeach tray.

2. The tray washing apparatus according to claim 1 wherein the trayreceiving means includes a plate having a passageway formed through itand including opposed surfaces for preventing the insertion of twostacked trays through the passageway, a blocking member normallypositioned in the path for preventing the insertion of trays through thepassageway and into the path, and means responsive to the insertion ofthe properly oriented tray through the passageway for moving theblocking member out of the path.

3. The tray washing apparatus according to claim 1 wherein the invertingmeans comprises means responsive to movement of each tray along the pathfor tilting the tray into a vertical orientation and for thereaftertilting the tray into a horizontal orientation in which the foodreceiving surfaces of the tray face downwardly.

4. The tray washing apparatus according to claim 3 wherein the invertingand dumping means discharges cleaning fluid onto each tray while thetray is in the vertical orientation.

5. The tray along apparatus according to claim 4 wherein the trayinverting and cleaning fluid dumping means is further characterized by afirst pivotally supported arm for engagement with each tray during themovement of the tray along the path and responsive to further movementof the tray along the path for tilting the tray into the verticalorientation, and a second pivotally supported arm responsive to furthermovement of the tray along the path for lowering the tray from thevertical orientation into a horizontal orientation wherein the foodreceiving surfaces of the tray faces downwardly, and means for pivotingthe second arm into engagement with the tray when the tray is in thevertical orientation.

6. In a ware washing apparatus, a refuse scrapping mechanism comprising:

means for moving ware each having a food receiving surface along apredetermined path; means responsive to movement of the ware along thepath for tilting the ware such that the food receiving surfaces thereofextend generally vertically;

means for dumping a predetermined quantity of cleaning fluid on the foodreceiving surface of each ware; and

means for actuating the cleaning fluid dumping means during the tiltingof the ware into the vertical orientation.

7. The refuse scrapping mechanism according to claim 6 wherein the warepositioning means includes means for moving a plurality of pieces ofware along a predetermined path, and wherein the cleaning fluid dumpingmeans dumps the same quantity of cleaning fluid on each piece of wareduring the movement thereof along the path.

8. The refuse scrapping mechanism according to claim 6 wherein the warepositioning means includes means for receiving ware with the foodreceiving surfaces thereof facing upwardly and means for inverting theware so that the food receiving surfaces face downwardly, and whereinthe cleaning fluid dumping means dumps cleaning fluid on the ware duringthe inversion thereof.

9. The refuse scrapping mechanism according to claim 6 wherein thecleaning fluid dumping means comprises a cleaning fluid reservoir andmeans for discharging substantially the entire contents of the cleaningfluid reservoir onto each food receiving surface.

10. The refuse scrapping mechanism according to claim 9 wherein thecleaning fluid dumping means is further characterized by:

means for normally positioning the cleaning fluid reservoir in fluidreceiving position,

means for directing cleaning fluid into the reservoir while it is in thefluid receiving position, and means for periodically tilting thecleaning fluid reservoir into a fluid dumping position.

11. The refuse scrapping mechanism according to claim 6 wherein thecleaning fluid entrains refuse and silverware as it passes over eachfood receiving surface, and further including a channel for receivingcleaning fluid that has passed over a food receiving surface and therefuse and silverware entrained therein, and means positioned in thechannel for disentraining silverware from the cleaning fluid.

12. In a tray washing apparatus, a refuse scrapping mechanismcomprising:

means for moving a tray along a predetermined path;

means responsive to movement of the tray along the path for tilting thefood receiving surface of the tray into a substantially verticalorientation;

a reservoir of cleaning fluid positioned adjacent the tilting means;

means for discharging substantially the entire contents of the reservoironto the food receiving surface of the tray while it is in the verticalorientation; and

means for coordinating the operation of the discharging means with theoperation of the tilting means, so that the cleaning fluid from thereservoir engages food receiving surface of the tray while the foodreceiving surface is oriented substantially vertically.

13. The refuse scrapping mechanism according to claim 12 furtherincluding means for supporting the cleaning fl'uid reservoir formovement between a fluid receiving position and a fluid dischargingposition, means for filling the reservoir with cleaning fluid while thereservoir is in the fluid receiving position, and

wherein the discharging means periodically moves the reservoir to thefluid discharging position.

14. The refuse scrapping mechanism according to claim 12 furthercharacterized by means for moving a plurality of trays along apredetermined path, wherein the orienting means includes means forinverting each tray during its movement along the path, and wherein thedischarging means empties substantially the entire contents of thecleaning fluid reservoir onto each tray during the inversion of thetray.

15. The refuse scrapping mechanism according to claim 12 furtherincluding common drive means for operating the orienting means toposition a tray substantially vertically and for simultaneouslyactuating the discharging means to pour substantially the entirecontents of the reservoir onto the food receiving surface of the tray.

16. The refuse scrapping mechanism according to claim 12 furtherincluding means for receiving fluid that has been discharged from thereservoir onto the food receiving surface of a tray, means for removingrefuse from the cleaning fluid, and means for returning the cleaningfluid to the cleaning fluid reservoir.

17. The refuse scrapping mechanism according to claim 16 wherein thecleaning fluid receiving means includes a channel for directing cleaningfluid into the refuse removing means, and means positioned in thechannel for disentraining silverware from the cleaning fluid.

18. in a ware washing apparatus, a refuse scrapping mechanismcomprising:

means for moving ware along a predetermined path;

a pivotally supported arm for cooperation with the moving means to pivotthe ware into a generally vertical orientation;

means for discharging a predetermined quantity of cleaning fluid ontothe food receiving surface of each ware; and

means for actuating the cleaning fluid discharging means during thetilting of the ware into the vertical orientation. 19. In a traycleaning system, the combination of: means for positioning a foodservice tray in a substantially vertical orientation and for thereafterpouring cleaning fluid on the food receiving surface of the tray todislodge refuse and silverware therefrom;

means including a chute for directing cleaning fluid and refuse andsilverware entrained therein away from the tray, along a predeterminedcourse, and for ultimately directing the cleaning fluid and the refuseentrained therein into a refuse receiving mechanism; means including adam positioned in the bottom of the chute for disentraining silverwarefrom the cleaning fluid and the refuse entrained therein, and

means for periodically removing silverware from the chute.

20. The combination according to claim 19 wherein the silverwareremoving means comprises a trapdoor formed in the bottom of the chuteupstream of the dam and means for periodically opening the trapdoor sothat silverware falls out of the chute.

21. The combination according to claim 20 wherein the cleaning fluiddirecting means includes a hopper for directing cleaning fluid andrefuse and silverware entrained therein into the chute and wherein thetray positioning and cleaning fluid pouring means includes a cleaningfluid reservoir and means for pouring substantially the entire contentsof the reservoir over the food receiving surface of the tray and intothe hopper.

22. The combination according to claim 21 further including means forcoordinating the opening of the trapdoor with the pouring of thecleaning fluid so that the trapdoor is opened when little or no cleaningfluid is flowing in the chute.

23. Apparatus for washing food service trays of the type including aplurality of food receiving compartments, comprising:

entryway means for receiving trays from the users thereof and includingstructure for preventing the 5 insertion of improperly oriented trays;

scrapping means for discharging cleaning fluid onto trays received bythe entryway means and thereby dislodging refuse from the trays; meansfor subsequently applying washing, rinsing and 10 drying fluids to thetrays, and

means for stacking the trays in a predetermined orientation.

24. The tray washing apparatus according to claim 23 wherein theentryway means further includes means for is preventing the insertion oftwo stacked trays and further including means for receiving andtransporting each properly oriented tray that is received by theentryway.

25. The tray washing apparatus according to claim 23 wherein theentryway means is further characterized by structure defining anaperture which prevents the insertion of vertically oriented trays andan upstanding member for cooperation with a slot in each tray torestrict the tray to insertion in a predetermined horizontalorientation,

26. The tray washing apparatus according to claim 25 wherein thestacking means stacks the trays in the same horizontal orientation.

27. The tray washing apparatus according to claim 23 wherein theentryway means further includes a member for normally blocking theinsertion of trays and means for moving the blocking member out of thepath of a properly oriented tray.

28. Apparatus for washing compartmented food service trays of the typehaving a plurality of food receiving compartments disposed betweenopposed edges and a groove extending the entire length of the trayincluding:

entryway means for receiving properly oriented trays from the usersthereof and comprising: an aperture including opposed surfaces forpreventing insertion of two stacked trays, a member for receiving thegroove of a properly oriented tray and thereby preventing the insertionboth of inverted trays and trays reversed in the horizontal plane,blocking means normally preventing tray insertion,

and means mounted for actuation by the edges of a properly oriented trayfor disabling the blocking means and thereby permitting tray insertion;means for receiving trays inserted through the entryway means and foradvancing the received trays along a predetermined path in timedsequence;

means responsible to movement of the trays along the path for tiltingeach tray into an orientation in which the food receiving compartmentsof the tray are oriented substantially vertically;

means positioned adjacent the tilting means for discharging apredetermined quantity of cleaning fluid into the food receivingcompartments of each tray;

means for coordinating the operation of the discharging means with theoperation of the tilting means, so that the cleaning fluid engages thefood receiving compartments of the tray while the food receivingcompartments are oriented substantially vertically;

means for subsequently sequentially applying washing, rinsing, anddrying fluids to each tray; and

means for finally stacking the trays in a predetermined orientation.

29 33 Um'mn STA'IES PATENT OFFICE CERT'JL'lEICATE OF CURRECTIQN PatentNo. 3,773,058 Dated November 20th, 1973 InV n LAWRENCE PETE KIT'I'ERMANIt is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 3, line 62 "amintain" should be --maintain-- Column 4, line 21"tray" should be --trays"-' Column 5, line 15 "Them" should be -Then-Column 6, line 27 "herein" should be -therein Column 6, line 61 "cam 15"should be -cam 158-- Column 12, line 16 "cam 136" should be --dam l36-"Column 13, line 36 "tray along" should be -tray washing-- Signed andsealed this- 16th day of April 197A.

(SEAL) Attest:

EDWARD M.FLETGHER,JR C. MARSHALL DAMN Atte sting Officer Commissioner ofPatents

1. A tray washing apparatus comprising: means defining a tray washingpath; tray receiving means positioned at the start of the path forconstraining trays entering the path to a predetermined orientation;means for transporting food service trays along the path with the foodreceiving surfaces of the trays initially facing upwardly; means forinverting each tray and for dumping a predetermined quantity of cleaningfluid onto the food receiving surface of each tray during the inversionthereof, and means for sequentially applying washing, rinsing and dryingfluids to each tray.
 2. The tray washing apparatus according to claim 1wherein the tray receiving means includes a plate having a passagewayformed through it and including opposed surfaces for preventing theinsertion of two stacked trays thrOugh the passageway, a blocking membernormally positioned in the path for preventing the insertion of traysthrough the passageway and into the path, and means responsive to theinsertion of the properly oriented tray through the passageway formoving the blocking member out of the path.
 3. The tray washingapparatus according to claim 1 wherein the inverting means comprisesmeans responsive to movement of each tray along the path for tilting thetray into a vertical orientation and for thereafter tilting the trayinto a horizontal orientation in which the food receiving surfaces ofthe tray face downwardly.
 4. The tray washing apparatus according toclaim 3 wherein the inverting and dumping means discharges cleaningfluid onto each tray while the tray is in the vertical orientation. 5.The tray along apparatus according to claim 4 wherein the tray invertingand cleaning fluid dumping means is further characterized by a firstpivotally supported arm for engagement with each tray during themovement of the tray along the path and responsive to further movementof the tray along the path for tilting the tray into the verticalorientation, and a second pivotally supported arm responsive to furthermovement of the tray along the path for lowering the tray from thevertical orientation into a horizontal orientation wherein the foodreceiving surfaces of the tray faces downwardly, and means for pivotingthe second arm into engagement with the tray when the tray is in thevertical orientation.
 6. In a ware washing apparatus, a refuse scrappingmechanism comprising: means for moving ware each having a food receivingsurface along a predetermined path; means responsive to movement of theware along the path for tilting the ware such that the food receivingsurfaces thereof extend generally vertically; means for dumping apredetermined quantity of cleaning fluid on the food receiving surfaceof each ware; and means for actuating the cleaning fluid dumping meansduring the tilting of the ware into the vertical orientation.
 7. Therefuse scrapping mechanism according to claim 6 wherein the warepositioning means includes means for moving a plurality of pieces ofware along a predetermined path, and wherein the cleaning fluid dumpingmeans dumps the same quantity of cleaning fluid on each piece of wareduring the movement thereof along the path.
 8. The refuse scrappingmechanism according to claim 6 wherein the ware positioning meansincludes means for receiving ware with the food receiving surfacesthereof facing upwardly and means for inverting the ware so that thefood receiving surfaces face downwardly, and wherein the cleaning fluiddumping means dumps cleaning fluid on the ware during the inversionthereof.
 9. The refuse scrapping mechanism according to claim 6 whereinthe cleaning fluid dumping means comprises a cleaning fluid reservoirand means for discharging substantially the entire contents of thecleaning fluid reservoir onto each food receiving surface.
 10. Therefuse scrapping mechanism according to claim 9 wherein the cleaningfluid dumping means is further characterized by: means for normallypositioning the cleaning fluid reservoir in fluid receiving position,means for directing cleaning fluid into the reservoir while it is in thefluid receiving position, and means for periodically tilting thecleaning fluid reservoir into a fluid dumping position.
 11. The refusescrapping mechanism according to claim 6 wherein the cleaning fluidentrains refuse and silverware as it passes over each food receivingsurface, and further including a channel for receiving cleaning fluidthat has passed over a food receiving surface and the refuse andsilverware entrained therein, and means positioned in the channel fordisentraining silverware from the cleaning fluid.
 12. In a tray washingapparatus, a refuse scrapping mechanism comprising: means for moving atray along a predetermined path; mEans responsive to movement of thetray along the path for tilting the food receiving surface of the trayinto a substantially vertical orientation; a reservoir of cleaning fluidpositioned adjacent the tilting means; means for dischargingsubstantially the entire contents of the reservoir onto the foodreceiving surface of the tray while it is in the vertical orientation;and means for coordinating the operation of the discharging means withthe operation of the tilting means, so that the cleaning fluid from thereservoir engages food receiving surface of the tray while the foodreceiving surface is oriented substantially vertically.
 13. The refusescrapping mechanism according to claim 12 further including means forsupporting the cleaning fluid reservoir for movement between a fluidreceiving position and a fluid discharging position, means for fillingthe reservoir with cleaning fluid while the reservoir is in the fluidreceiving position, and wherein the discharging means periodically movesthe reservoir to the fluid discharging position.
 14. The refusescrapping mechanism according to claim 12 further characterized by meansfor moving a plurality of trays along a predetermined path, wherein theorienting means includes means for inverting each tray during itsmovement along the path, and wherein the discharging means emptiessubstantially the entire contents of the cleaning fluid reservoir ontoeach tray during the inversion of the tray.
 15. The refuse scrappingmechanism according to claim 12 further including common drive means foroperating the orienting means to position a tray substantiallyvertically and for simultaneously actuating the discharging means topour substantially the entire contents of the reservoir onto the foodreceiving surface of the tray.
 16. The refuse scrapping mechanismaccording to claim 12 further including means for receiving fluid thathas been discharged from the reservoir onto the food receiving surfaceof a tray, means for removing refuse from the cleaning fluid, and meansfor returning the cleaning fluid to the cleaning fluid reservoir. 17.The refuse scrapping mechanism according to claim 16 wherein thecleaning fluid receiving means includes a channel for directing cleaningfluid into the refuse removing means, and means positioned in thechannel for disentraining silverware from the cleaning fluid.
 18. In aware washing apparatus, a refuse scrapping mechanism comprising: meansfor moving ware along a predetermined path; a pivotally supported armfor cooperation with the moving means to pivot the ware into a generallyvertical orientation; means for discharging a predetermined quantity ofcleaning fluid onto the food receiving surface of each ware; and meansfor actuating the cleaning fluid discharging means during the tilting ofthe ware into the vertical orientation.
 19. In a tray cleaning system,the combination of: means for positioning a food service tray in asubstantially vertical orientation and for thereafter pouring cleaningfluid on the food receiving surface of the tray to dislodge refuse andsilverware therefrom; means including a chute for directing cleaningfluid and refuse and silverware entrained therein away from the tray,along a predetermined course, and for ultimately directing the cleaningfluid and the refuse entrained therein into a refuse receivingmechanism; means including a dam positioned in the bottom of the chutefor disentraining silverware from the cleaning fluid and the refuseentrained therein, and means for periodically removing silverware fromthe chute.
 20. The combination according to claim 19 wherein thesilverware removing means comprises a trapdoor formed in the bottom ofthe chute upstream of the dam and means for periodically opening thetrapdoor so that silverware falls out of the chute.
 21. The combinationaccording to claim 20 wherein the cleaning fluid directing meansincludes a hopper for diRecting cleaning fluid and refuse and silverwareentrained therein into the chute and wherein the tray positioning andcleaning fluid pouring means includes a cleaning fluid reservoir andmeans for pouring substantially the entire contents of the reservoirover the food receiving surface of the tray and into the hopper.
 22. Thecombination according to claim 21 further including means forcoordinating the opening of the trapdoor with the pouring of thecleaning fluid so that the trapdoor is opened when little or no cleaningfluid is flowing in the chute.
 23. Apparatus for washing food servicetrays of the type including a plurality of food receiving compartments,comprising: entryway means for receiving trays from the users thereofand including structure for preventing the insertion of improperlyoriented trays; scrapping means for discharging cleaning fluid ontotrays received by the entryway means and thereby dislodging refuse fromthe trays; means for subsequently applying washing, rinsing and dryingfluids to the trays, and means for stacking the trays in a predeterminedorientation.
 24. The tray washing apparatus according to claim 23wherein the entryway means further includes means for preventing theinsertion of two stacked trays and further including means for receivingand transporting each properly oriented tray that is received by theentryway.
 25. The tray washing apparatus according to claim 23 whereinthe entryway means is further characterized by structure defining anaperture which prevents the insertion of vertically oriented trays andan upstanding member for cooperation with a slot in each tray torestrict the tray to insertion in a predetermined horizontalorientation.
 26. The tray washing apparatus according to claim 25wherein the stacking means stacks the trays in the same horizontalorientation.
 27. The tray washing apparatus according to claim 23wherein the entryway means further includes a member for normallyblocking the insertion of trays and means for moving the blocking memberout of the path of a properly oriented tray.
 28. Apparatus for washingcompartmented food service trays of the type having a plurality of foodreceiving compartments disposed between opposed edges and a grooveextending the entire length of the tray including: entryway means forreceiving properly oriented trays from the users thereof and comprising:an aperture including opposed surfaces for preventing insertion of twostacked trays, a member for receiving the groove of a properly orientedtray and thereby preventing the insertion both of inverted trays andtrays reversed in the horizontal plane, blocking means normallypreventing tray insertion, and means mounted for actuation by the edgesof a properly oriented tray for disabling the blocking means and therebypermitting tray insertion; means for receiving trays inserted throughthe entryway means and for advancing the received trays along apredetermined path in timed sequence; means responsible to movement ofthe trays along the path for tilting each tray into an orientation inwhich the food receiving compartments of the tray are orientedsubstantially vertically; means positioned adjacent the tilting meansfor discharging a predetermined quantity of cleaning fluid into the foodreceiving compartments of each tray; means for coordinating theoperation of the discharging means with the operation of the tiltingmeans, so that the cleaning fluid engages the food receivingcompartments of the tray while the food receiving compartments areoriented substantially vertically; means for subsequently sequentiallyapplying washing, rinsing, and drying fluids to each tray; and means forfinally stacking the trays in a predetermined orientation.